Look forward to it, I'm sure that it will be interesting.
There was a firm in Bedfordshire - Minitrac - who did a lot of grey imports, mainly from France, of Kubotas and Issekis but I see that the company was dissolved in 2014.

I'll go along with that. Expensive to buy new but due to the quality of the engineering had modest running costs - unlike many cheaper machines. Is there some history with it such as why was it apparently abandoned to the elements?

Yes, Westwoods were made in the 70s . Not sure how far back for the tractor shaped ones but they were definitely around pre 80s. I had a Lawnbug early 70s or even late 60s!!!!
We used to see the trans drive belt dropped off the big pulley on the top of the trans and used to fit a peg keeper down from above just to stop it falling clear of the pulley when de-clutched.
Did you post this query somewhere else a while back? In answer to whoever did I posted the part numbers for two pulley mod kits for the "zig zag pulleys that did the de-clutching. I'll dig them out again and add them to this post.
EDIT
3230 and 5823 Both on our stock file as "idler pulley mod kits" .Obviously meant something back in the day but may have no relevance to your question!

I hope that you get sorted out . I had a vague recollection of pulley issues with Westwoods of that era and modified pulleys being introduced. If pushed I'd say that they were deeper metal ones . I've had a look at our old stock file and there are two part numbers for "Pulley mod kits" part numbers 3230 and 5823 but no indication of what or why.

Interesting to read how well the hot air treatment works. I have tried to brighten up faded Flymo decks with all the usual cutting compounds and polishes but other than putting a shine on the faded plastic, no improvement. If it comes to a repaint you will need to roughen it up with 400 wet or dry and then apply a plastic specific primer as used by car bumper repairers and probably available at Halfrauds.
Al-ko, beside being a major manufacturer of caravan, motorhome and trailer chassis, make some decent garden machinery.
Way back in the 80s they made a grass collecting ride on where the deck exited to a rectangular tube with a conveyor belt inside it carrying the grass to a big upright bin at the rear.

A bit late now but have just unearthed an old Dayco belt catalogue which cross references that 7473 number to their ref L582, ie an L5 section, 82" long. L5= 5/8", 16mm
In belt measuring language Li =inner length, La= outer length , Lw/Ld = working length and Le = effective length and somewhere along the line some manufacturers refer to a "mean pitch length" !

Not Turning over on the key/ starter and turning over but not firing up are two different issues with different factors affecting them.
Just in case you have got a live supply to the kill wire , disconnect it. If you suspect that you may have already given the coil a dose of volts , remove the engine cowl / blower housing and inspect the coil . If it has been zapped it will usually be swollen and maybe charred.
Now to test and identify the non cranking condition . Locate the starter solenoid which will have a heavy cable from the battery to one top terminal and a heavy cable from the other top terminal to the starter motor. The battery side terminal may also have a smaller diameter cable; that is to supply charge - don't worry about it for now. The solenoid will also have a lighter terminal near its base ( may have two small terminals but let's just assume one or now.
Pull the connector off the small terminal and take a length of cable and hold one end onto the battery positive and touch the small solenoid terminal with the other end. Hopefully the starter motor will engage. If it doesn't you have either a bad solenoid or motor. If the engine cranks with the direct feed from battery to solenoid the problem is either with your wiring, the ignition switch or a safety circuit/ switch.
there are more brutal things you can try like shorting out the solenoid but stick with the more civilised tests for now.
Edit. Check list.Before you start.
Fully charged battery
Tight battery terminals
Battery negative / earth , clean and tightly bolted to the chassis.
If the engine is bolted directly to the chassis - which on a Westwood it usually is- check the tightness of the mounting bolts. If the engine is on Anti- vibe mounts check that any earth strap between the block and chassis is clean and tight.
Check that any fuses are present and intact.